It is known that the performance of a turbojet can be improved and/or that its noise level can be reduced by varying the flowsection for air from the fan as a function of flying conditions. Thus, compared with the section that is normally appropriate for cruising conditions, improved performance can be obtained during takeoff or landing by reducing said section. For this purpose, it is known to place a ring of flaps close to the trailing edge of the nozzle, the flaps being movable and being controlled so as to retract towards the axis of the turbojet, thereby reducing the flowsection for the air flowing through the fan. The flaps are generally actuated by actuators, thereby adding considerably to the weight of the mechanism.
Document US 2006/0101803 describes a nozzle in which the trailing edge is provided with deformable panels known as “chevrons” that include inner tendons of shape memory alloy and of curvature that is determined by temperature. The curvature imposed by the tendons (which depends on their temperature) is transmitted to the panels. The electrical control means are simpler and lighter in weight, but the structure of such a panel remains complex.